Environmental geology in loess areas of China

There are several unfavorable geological hazards in the loess area of China. The major purposes of environmental geology studies in this region are to expound the causes of these hazards and to determine treatments. Geological hazards include endemic diseases, depletion of groundwater, land subsidence, ground fissures, soil erosion, and collapsibility of loess. This article is a summary of studies regarding these hazards. Keshan disease and Kaschin-Beck disease, for example, can be prevented and cured by adding selenates to table salt. Ponds can be constructed on the loess plateau and dikes around farmlands to collect rainfall to recharge groundwater resources. Excess extraction of groundwater is the major cause of land subsidence. Ground fissures in Xi'an are primarily caused by tectonics, but over-extraction of ground-water strengthens its activity. Observation stations should be established in order to forecast and prevent landslides. Planting trees in a regional shelterbelt is the primary measure necessary to prevent soil erosion. As a result of these geological studies, valuable experience in preventing collapse of loess in China has been gained.